News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Main menu

Search form

You are here

Sterile Sourdough X

April 10, 2011 - 11:36am

jcking

Sterile Sourdough X

This is a follow up to the "Sourdough Water" post.

This experiment is to determine if wild things can be captured by sterile flour and water. One week ago the water and flour were sterilized, covered with cheese cloth and allowed to sit (attempting to capture wild yeast and bacteria). Durum flour and spring water were used. Durum was chosen because, I just received a fresh bag from KA, and it contained no additives. According to D Leader bakers in southern Italy (Puglia region) use Durum for their sourdough.

The experiment will follow P Reinhart's (Artisan breads every day) 75% Pineapple juice build, except that the pineapple will be added later to the disgarded SD for comparison. My current mother is from this procedure and has proved successful.

Day One; 30g flour mixed with 30g water in a glass 2 cup measuring cup, covered with plastic, at 74 F room temp. (I gram everything) To be stirred 3 times daily; when I awake, before I retire and once in between.

Why not use this as a control and run some more experiments at the same time? To sort of take the long waiting out of it... I would still use pasteurized unsweetened pineapple juice because your mixture will need all the pH help it can get!

I'm sure that without an autoclave, something will grow in there. ------> I*I

I'm grams all the way, no cups for me:) Sure, what's you're ideas for another variation? I'll wash everything same as usual, yet I have an open invite for wild critters. My thought was to start sterile and see what happens.

I'm holding off on the P juice because I want to give whatever lands in the flour or water a chance to survive for a while. There may be symbiotic relationships between the critters that we do not yet understand.

I've always been a what if guy and try (or think) something different along the way. My latest view is that I never fail at anything, I just learn something new. As always, thanks for your input.

you can 'start sterile' against certain known critters, but unless you have a "clean room" that would make micro-chip manufacturers jealous, your 'sterility' lasts a few seconds, only...sorry, but that's LIFE...LITERALLY!

Walking in the room will infect your sterile environment, as will breathing, sniffing, coughing, sneezing, wearing clothes, being naked, owning a pet, using heaters, coolers, vents, or even being near a source of water or other moisture...

I'd stay well-away from the kitchen if I wanted a 'sterile' experiment. But good luck, anyway! ;-)

Mini's post was 'spot-on', too, though! Old hands at sourdough baking are often suspicious of the word "capture" and that's probably the only 'spark' that sets these discussions off, as far as I can tell. Yeast spores abound, everywhere, even in recently-sterilized jars.

I used very rough German rye flour and European mineral water for my first starter and I wished/hoped/prayed(?) that the native German yeast spores that were already attached to the pieces of husk would dominate my sourdough culture. (I have no way of telling whether they did, or not) but my rye breads impressed my German (and other European friends) enough to have them ask me to make bread for them on a regular basis. I had to refuse, of course, because of my tiny ovens and lousy work schedule; (alternating late and early shifts...great for bakers, actually, if one doesn't need to sleep, or to earn money in other ways, between those times!)

With coarse wholemeal or rye flour you will already have a huge 'population' of many different yeast spores, just waiting to feed on the sugars available from the starches in the flour. Whether some of the many 'local' yeasts in your kitchen take over is a matter of environment and evolution. It's really beyond our control. Bacteria also abound and you're going to have an even tougher time with them. Controlling the acidity, as Mini said, will give you a better chance of the 'good guys' winning. If you live in San Francisco, though...GO FOR IT! (and may you have far fewer earthquakes than I've been experiencing!)

yesterday eve; seed that began as semi-firm ball settled into paste. One pellet size bubble observed. It was stirred and left to sit, covered, overnite.

Day Two; Stirred seed. Although I imagined the seed would grow slower than normal, there are many bubbles. About half the ones I should have by day three. Did take picture - camera cable missing in action - will post when I can.

Went shopping for Litmus Paper, Ended up with free sample (10 strips) of AQUATEST, from pool supply store. Tested water and seed culture.

Water; Chlorine=0, PH=6, Alkalinity=20

Seed; Chlorine=0, PH less than 6 (test result strip only showes 6 or above), Alkalinity=60

probably have nothing to do with yeast...that's almost certainly bacterial action (as you probably know...)

The pH sounds low enough for the 'good' bacteria to be reproducing, but I wouldn't know for sure if they're really the 'good ones' that have taken over. If they are, your yeast spores may soon start some real bubbling action. Time will tell!

I LOVE that 'sweet smell' phase the starter goes through! In a couple of days you should find some yeasts 'waking up' and starting to feed...if you get a major rising you could try baking with it a few days later (which most sources tell you NOT to do) but it's an 'experiment', right? Give it a try!

As soon as it looks good, you bet, I'll be giving it a go. I want to taste the difference and test the rise as it reaches full development. One thing I'm noticing is the bubbles are getting smaller and more numerous.

I'm thinking the sweet is somewhat from the durum. Also looking at Durum Bread recipies from D Leader's Local Breads.

Stirred twice so far today, will stir again before night fall. PH less than 6, Alk=60, no change. Smell turned slightly sweet/sour. Before morning and midday stirring, there was a decrease in bubbles; an hour after stirring bubbles returned.

I just checked out that link and it's probably ME that's wrong, but those pH figures quoted in the other, older, thread looked WAY too low to me.

My pH meter is a pretty good one; not the most expensive one on the market, I admit, but it's well-calibrated. [pH7.0 for distilled or purified water, pH13.8 or higher for NaOH.] I almost always get a reading of pH4.6-4.8 for my 100% hydration all-rye starters, when they're just useable and probably looking for a feed. This seems perfect for my rye baking.

When I use them for mixed flour (mostly-white) breads, they border on being a bit too sour. (I use very long fermentation times, though.) The lowest figure I ever measured for a very reliable starter was before I used a scale and that was about pH4.3. The bread had good 'keeping' qualities, but the sour flavour was a bit over-powering for some people. Any comment or insights? Thanks!

Point being that a swimming pool dip stick doesn't test low enough for a starter that needs feeding. I agree that pH 4.3 is sour and pH 3.5 (should it drop that low) is a real lip twister but I think that's where this experiment is going. This experiment started with flour and water pH and then slowly got more acidic (drop in the pH.) That will continue or it will get dominated by something along the way and maybe change. Checking pH would be safer than tasting for sour. When the pH is low (copyu, you mention pH 4.3) then yeast activity without any additional food would taper off. The acid is a preservative fending off invading organisms. If the pH stays above 5, chances are good something else will invade it and it might not be so nice as a known sourdough culture.

This experiment is one in just sterilizing water and flour and observing without an end in sight. That's how I understand it. correct? With the hope that it becomes a growth medium for a sourdough culture starter, right?

Comments that the pH is the same every day and hasn't changed cannot be true if the mixture cannot be tested below pH 6. Because sourdough starter cultures have a pH lower than 6, I suspect the pH is gradually falling or fluctuating. I'm sure I'm not the only one thinking along these lines.

An interesting question would be to know how low the pH range extends on a non-sour tasting sourdough culture? What does it produce or how does it protect itself?

I hope you picked up the "Champ" model...only 50 bucks, too! [Fumes of envy...]

A lot of pH meters on the market are very "application-specific", eg: garden or potting soil, aquarium water, or alcoholic beverages. They have much greater accuracy (more decimal places) but measure very limited ranges.

The "Champ" is dead-accurate at the 'neutral' reading, which means it's a general-purpose meter. The accuracy would probably fall off at the high and low ends of the scale, obviously, but it's a brilliant instrument for my needs (and yours.)

I like to rinse it in distilled water or Aqua Purificata between measurements and make sure that it reads exactly 7.0 before switching to another test medium. I always do my tests, now, for 5 minutes as it sometimes takes that long for 'fluctuations' to stop. (I used to use 3 minutes, but I think that's too short, now.)

Sorry I didn't clarify (daughter visiting from Boston, very distracted in my posts.) I ment that I ordered a tester not the model you own. I ordered a Oakton Ecotester PH2 along with calabration liquids. Delivery 4/21. Sorry for the confusion.

Since the feeding, the sweeter smell has returned along with big bubbles that appear about an hour after stirring. If the seed starts to expand within the next few days I'll be happy, if not I think it may just be a bacterial pool.

Now I'm not sure if the litmus paper reading is true. After dipping a piece of litmus into of the seed, which has remained yellow because I used durum, some of the sticky seed remains on the paper and that may effect the color I'm seeing. I'll have a better idea once the PH tester arrives. I also let the seed go longer between refreshment because I felt the wild buggers needed more time to grow.

Someone suggested I run a comparison test along with the X test. I should have followed that idea since none of my starters included Durum flour. I'm going to start a new test in a week or so with the same sterile flour and a non-sterile flour to compare. I've found a starter formula in Leader's Local Breads that uses only Durum flour. It's an Italian thing. It also has yogurt in the seed. I'd like to hear views from TFL members as to whether the yogurt may throw off the test because it adds bacteria and maybe some wild yeast.

Day 8 & 9 were showing no progress even though I stepped up the stirring to about once every two hours. After stirring big bubbles would appear yet no expansion. I was thinking oh bother, nothing ventured nothing gained.

Last night I noticed smaller bubbles starting to form, yet couldn't say it was expanding. When I took a look this morning BAM! It had expanded to tripple it's size - I almost fell over.

So now I'm on to step 4 adding more sterile water and flour. I'm a happy boy!

I have a slightly different view of starters since I've run this experiment. I've also done a lot more reading on the subject. I'll answer your questions with what I have observed so far.

1.When launching a starter the yesat and bacteria on the flour will dominate. As things progress they may change. You can probably count on at least 3 or more varieties of wild yeast and a few dozen bacteria; more so on organic, in a typical flour. Over 50 yeasts and 100 bacteria have been found in tested sourdoughs and flours around the world. They all may be present everywhere yet they need food to grow and multiply.

Only the strong survive in the envirornment they are exposed to. We as home bakers are in an entirely different realm than the pro baker, especially when dealing with sousdough. We may have pets, house plants, fresh fruit & veggies on the counter and so on. Some believe the San Fran bacteria is carried by humans.

2. I firmly believe there are yeasts and bacteria all around us that could survive better than the buggies in the flour. Things that find food that suits them will grow and multiply, Take evolution for example and how man has changed and adapted to his enviornment. So I believe that the flour and water should be left open to the enviornment, keep the seed covered. I would even say leave the flour and water out for a couple of weeks before one begins.

3. Most people say that their sours mature in flavor over the first few weeks. I believe this is where the yeasts and bacteria decide who gets what sugar. As the enzymes break down the starches into simple sugars, the beasties feed. If a beasty finds a good sugar and there's no competition off it goes. It is quite possible that the beasties on the flour will do well and dominate, or others could invade. Other things to consider are local climates, temperature varients and humidity. I'm wondering if changes in atmospheric pressure would effect dough rising.

The flour I chose, Durum, didn't even include barley malt or ascorbic acid, yet it worked. Believe me I'm as surprised as anyone elsa that this experiment worked and worked within two weeks. I was sure I could capture bacteria but I was leary about the yeast. I thought I'd end up with bacterial gas and the bread would barely rise. Yet I got a nice rise, a nice proof and good oven spring. And it tasted good. I've never had bread made with 100% Durum so I have no base for comparison.

Having done this X I believe it is very important to stir the seed (proto-starter) at least 3 times a day, every 2 hours of the waking day the max. Seems some of the beasties need air.

I'm wondering by baking the flour and killing all the beasties, we don't have to worry about any bad beasts that came with the flour.

I've been doing the same thing (in theory) for the past few days myself. I've used some unbleached flour that was a couple days to a week old (meaning not "fresh from the store"), left in a sealed container, to begin the starter with. Not the fresh rye and whole wheat that I've seen most people claim is the key to a starter; that the yeast is on the outside of the wheat grains, and the farther away you get from picking your own wheat and grinding it directly into the bowl you're going to make the starter in, the less chance you have for a natural yeast starter. However, I've been using 1/4 cup unbleached, and "split" a quarter cup measure with water, beer, and the tiniest splash (a tsp. or so) of lemon juice for further pH control. (I would imagine the added low alcohol content of this mix will help with bacteria suppresion). At day 3 now, followed the "general" rules up until the discard stage (just add equal amounts liquid and flour, still made up of a mix of water, beer, and lemon juice). Day one smelled horrible...kind of like beer, flour, water, and lemon juice. Day two was the same, but with a slight tinge of "ugh" to it. Today at 3:00 EST was the end of day three. Smells yeasty (i'd imagine it's just from the beer at this point), with the slightest acidic twinge, but not unpleasant at all (much better than yesterday). The next week, however, will be the proof. (hahaha...)

Wow. With lpinpoint accuracy, you've hit the one thing I've forgotten. Obviously, it got stirred well when feeding, but didnt think much of it other than that. Makes sense though...If i'm going making a trap, I need lots of surface area. Stirring probably increases surface area on the order of hundreds-or-thousands-fold, so that probably just saved my experiment (if there's a chance of survival to begin with)...thanks

(by the way...this website helped me go from making pizza dough (with no knowledge of baking) in a floor mixer at a "restaurant" to making bread, rolls, bagels, pretzels, etc. by hand last 9 months or so at home. This is probably one of the greatest bread making resources I've come across, and told me EVERYTHING I needed to know short of actually being able to feel what good dough felt like, which I got from the restaurant. I've been making good bread for about 6 or 7 months now, and it's one of the most rewarding ways I spend my time...thanks for massing all of this experience into one quick location)

I've always assumed that the "sterile" in your experiment meant you did something like heat your flour. But as I look back, the (mis?)interpretation that "sterile" simply means "covered ever since the sack was opened" could also be consistent with everything that's explicitly stated. So just for us sticklers for completeness, could you tell us explicitly just how you "sterilized" your flour?

(There are tons of yeast spores even in freshly purchased and opened flour, right? In fact, comparing the yeast "in the air" with the yeast "on the flour" is the main point of your experiment, right?-)

There was more info in the precursor to this post under sourdough water. Following a suggestions from Ford; the bag of Durum was placed in a large ovenproof bowl. The oven was preheated to 350F for 30 mins, the flour was placed in the oven and baked for 30 mins. This should have killed any wild beasties. After the bowl was allowed to cool it was covered with cheese cloth and placed in the dinning room. In addition a gallon of water was boiled for 30 mins. I really don't know if boiling was needed, it just seemed like a good idea at the time.

I posted a pic of my first loaf in the sourdough section Under "Altumura Tantrum Loaf" but my spelling might be off. I'm keeping a sour Durum starter and plan to do an informational report as to how it developes. So far it's rising the bread well, yet the flavor is mildly sweet with no sour. Yet this may be because of the recipe (Leader's book) for an Italian bread that isn't meant to be sour. Some Italian and French sourdoughs are designed not to be very sour. Some German Rye recipes add hot water to the build to reduce the sour. This info comes from Leader's book. Sourdoughs around the world can be quite different in the final loaf.

Thanks for the interest, Sometimes one may make a post and wonder if anyone read it:)

I was taught to always have a "control" and that would be in this case a jar with the baked flour (boiled jar too) boiled water and a lid to cover. It doesn't get opened or stirred or anything. It just sits there all mixed up without the use of a spoon. If nothing happens to it, while "X" is being played with, then everything was sterile. If something grows in it, then there is a big flaw in the whole experiment as it would mean that the flour/water was not heated long enough to kill all the beasties and their spores. Spores are especially tough.

I agree that a comparison would have provided more of a proof. A few weeks ago I joined the Bread Bakers Guild forum @ Yahoo which has University papers by science types. In some of those tests it is mentioned that yeasts and bacteria will die at temps above 175F (spores weren't mentioned) so there may be some validation in what I've done. Yet we must remember they were using lab conditions and I'm a humble home baker.

With summer almost here my play time is more limited. So I intend to retry my X come this fall. In the meantime I'll be considering how to set up a better evaluation. I'm more than open to any comment from the group as to the set up.

As I look back at how the X developed I may have had some unintended help. As stated above the flour and water were kept in the dinning room. As they were sitting there, covered only with the cheese cloth, my wife had moved a plant from the porch (because of one of the big storms the south had lately) to within a foot of my X flour and water. A day or so later a bowl of fruit also appeared on the other side. Migration?

As to what's in the X now, I don't have any way to test what yeast or bacteria it may hold. I've measured the Ph and it remains, so far, at 4.5. The loaves I've made so far have risen nicely, the oven spring was good and no one has gotten sick :-). So one could say there are beasties of some kind,

I thanks you for your input and hope to hear/see more. Two heads are better than one.

Recent Forum Posts

All original site content copyright 2016 The Fresh Loaf unless stated otherwise. Content posted by community members is their own. The Fresh Loaf is not responsible for community member content. If you see anything inappropriate on the site or have any questions, contact me at floydm at thefreshloaf dot com. This site is powered by Drupal and Mollom.